Coating polyethylenimine

Carlisle RC, Etrych T, Briggs SS, Preece JA, Ulbrich K, Seymour LW (2004) Polymer-coated polyethylenimine/DNA complexes designed for triggered activation by intracellular reduction. J Gene Med 6 337-344... 

The other possibility is to coat the silica with a polymer of defined properties (molecular weight and distribntion) and olefin groups, e.g., polybutadiene, and cross-linked either by radiation or with a radical starter dissolved in the polymer [32]. This method is preferentially used when other carriers like titania and zirconia have to be surface modified. Polyethylenimine has been cross-linked at the snrface with pentaerythrolglycidether [41] to yield phases for protein and peptide chromatography. Polysiloxanes can be thermally bonded to the silica surface. Other technologies developed in coating fnsed silica capillaries in GC (polysiloxanes with SiH bonds) can also be applied to prepare RP for HPLC. 

Titanates have been instrumental in the bonding of fluorinated resins to packaging films, poly(hydantoin)—polyester to polyester wire enamel, polysulfide sealant to polyurethane (a phosphated titanate is recommended), polyethylene to cellophane using a titanated polyethylenimine, and silicone mbber sealant to metal or plastic support using polysilane (Si—H) plus polysiloxane (Si—OR) and titanate as the adhesive ingredients (450—454). Polyester film coated first with a titanium alkoxide, then with a poly(vinyl alcohol)—polyethylenimine blend, becomes impermeable to gases (455). 

Liu et al. used polyethylenimine (PEI) to stabilize R " " and subsequently control the growth of NaYp4 NCs. The as-obtained PEI-coated NCs were... 

Coating Technique This technique usually deposits a hydrophUic layer such as HEC, polyvinyl alcohol, chitosan, polyacrolein, and polyethylenimine on a hydrophobic one [13,71,85,86]. The coating layers prepared are, however. 

PEI-Mag2 precipitation/coating solution 2.5 g polyethylenimine 25 kD, branched (PEl-25gj. Sigma-Aldrich) plus... 

Polyethylenimine The crystal is coated with a methanol solution containing 2-3% polyethylenimine. After treating the precoated crystal with glutaraldehyde, biocatalysts can be immobilized on the precoated crystal via the surface aldehyde groups [29]. 

Polyethylenimine The crystal is first coated with a polyethylenimine and avidin 19 solution (2-3%). Avidin is then immobilized on the coated crystal via glutaraldehyde activation. The biotinylated biocatalyst is immobilized on the coated crystal via biotitr-avidin interaction since one molecule of avidin binds four molecules of biotin [29]. 

The NS-100 membrane (initially designated as NS-1) was the first noncellu-losic composite membrane to appear in the published literature and have an impact on the reverse osmosis scene.22/23 This membrane, invented by Cadotte,24 consisted of a microporous polysulfone sheet coated with polyethylenimine, then interfacially reacted with either 2,4-toluenediisocyanate (TDI) or with isophthaloyl chloride (IPC). In the first case, a polyurea is formed in the second case, a polyamide. The chemistry of this membrane is as follows ... 

The NS-100 membrane is capable of giving salt rejections in excess of 99% in tests on salt solutions simulating seawater (18 gfd, 3.5% synthetic seawater, 1,500 psi, 25°C). If the polyurea interfacial reaction step is omitted, and the polyethylenimine-coated polysulfone film is heat-cured as usual, a crosslinked polyethylenimine semipermeable barrier film is generated. This membrane gives 70% salt rejection and 55 gfd water flux under the same test conditions as above. Also, if the fully formed NS-100 membrane is dried at 75°C, which is too low a temperature to effectively crosslink the amine layer, the resulting film will exhibit a salt rejection of 96% or less. 

In the thesis of polyethylenimine-coated supports there is variability introduced by the polyamine as well as the cbrace of ooss-linker employed. For instance, cross-linking is prevalent during the polymerization of ethy-lenimine and there is normally a distribution of 25% primary amines, 50% secondary amines, and 25% tertiary amines (.101). Berause of the chemical variability in these stationary phases several methods, such as the use of test solutes of varying hydrophobidty and static adsorption isotherms, have been employed in the duuacterization of these phases (37-40,102). 

Table VIdesoibes the further derivatization ofapolyethylenimine-coated support, possessing an underivatized picric add exchange capacity of. a 280 Amol N/g support 40). Various monoepoxides containing a range of chemistries were bonded on to the polyethylenimine-support. As the chemical nature of the support changed relative retention of test proteins varied.

Polyethylenimine-coated supports have been used in the separation of proteins, nucleotides, and sinde>stranded oligonudeotides. These coated... 

As an example, Alpert and Regnier (26) coated silica with polyethylenimine 6 and crosslinked the product subsequently with a suitable crosslinker. Their preferred crosslinker was pentaerythrol tetraglycidyl ether. The coating was also applied to alumina and titania, and lately to zirconia (27). 

The coupling of the CZE step to detection systems other than UV has required the development of separation conditions compatible to the detection system used. For instance, the presence of primary amines, such as DAB, in buffers needed to be avoided for compatibility with laser-induced fluorescence (LIE) of compounds derivatized with fluorogenic substrates through their amino groups [90]. Baseline resolution of eight peaks in approximately the same time was achieved by substituting DAB by morpholine and tricine by boric acid (to avoid potential traces of primary amines in the tricine buffer) and by adjusting the concentration of other buffer components to compensate for the increase in electrical current. In the same work, modifications were also required to achieve compatibility with MS detection where nonvolatile salts, urea, and amines should be usually avoided. A physically adsorbed polyethylenimine-coated capillary was used to overcome protein adsorption to the capillary walls in the absence of cationic additives and the use of an acetate buffer at pH 5.05 allowed the partial resolution of at least five bands of rhEPO. Other types of coated capillaries have been used for the analysis of EPO by CE-MS as detailed in Section 22.4.3.3 [30,37,42,62,96]. 

Cordova et al. explored the CE behavior of protein charge ladders obtained by acetylation of lysozyme and carbonic anhydrase II using noncovalent polycationic coated capillaries. Two of them, polyethylenimine and Polybrene, were very effective in preventing the adsorption of positively charged proteins. Conditions used were fused-silica capillary (50 p.m i.d. x 38 cm) coated with the polymer by flushing the capillary with a 7.5% (w/v) polymer solution, prepared in 25 mM Tris-192 mM Gly buffer (pH 8.3), for 15 min. The running buffer was 25 mM Tris-192 mM Gly buffer (pH 8.3) in the absence of polymer. Separations were obtained within 5 min. 

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